1. Field of the Invention
This invention relates generally to the treatment of flowing water or other liquids, and more particularly to the treatment of such liquids with a ringing electromagnetic pulse.
2. Description of the Background Art
Various different devices and methods have been proposed for treating liquids with electromagnetic flux for the purpose of reducing the scaling propensity of the liquids, for reducing the number of living microorganisms contained in the liquids, or for other purposes. Some of these prior devices have used either stationary or movable permanent magnets for producing a magnetic flux. Other devices have used electrical coils arranged in various different ways with respect to pipes conducting the liquid wherein the coils are energized by either a direct current power source or an alternating current power source to create an electromagnetic flux used as the liquid treatment factor.
U.S. Pat. No. 5,702,600 to Pandolfo discloses a variable resonance descaling decalcifier device connected to a forced sequential rephasing transformer. The device of this patent uses an apparatus including a plurality of electrical coils surrounding different separate longitudinal sections of a liquid conducting pipe to provide an electromagnetic flux for the treatment of water. In the apparatus, two of the coils are wound on top of one another, and an ordinary diode is connected in circuit with the coils and with the power source, such that current from the power source is conducted through the coils only during alternate half-cycles of one voltage polarity wherein some current of a ringing nature apparently flows through each coil following the end of each half-cycle of diode conduction. However, the ringing current, and the electromagnetic flux produced appears to be weak and of very short duration so as to be of small effectiveness.
U.S. Pat. No. 6,063,267 to Crewson et al., the disclosure of which is herein incorporated by reference, discloses an apparatus for treating flowing liquid with electromagnetic flux. The apparatus of this patent treats flowing liquid with electromagnetic flux. The commercial embodiment of the device is sold under the trade name “Dolphin.” The Crewson et al. apparatus creates or applies magnetic fields of a repetitive nature in a flowing fluid. Such magnetic fields are the natural response of an induction coil or coils to an abrupt cessation, or other abrupt change, of the flow of current through the coil or coils. This phenomenon is known as “ringing.”
The precipitation of calcium carbonate as powder rather than scale and the control of biological activity are directly ascribed to the existence of these electrical and magnetic fields. Powder precipitation has been ascribed to a reduction or elimination of the surface charge, that is normally present on colloidal particles, by the time varying electric and magnetic fields. The reduction in surface charges substantially reduces or eliminates the electrostatic repulsion between these particles, which, in turn, increases collisions between particles resulting in rapid particle growth and settling (as opposed to scaling on heat transfer surfaces). The control of biological activity has been ascribed to encapsulation of bacteria in the precipitating calcium powder, as previously described, and to a direct interaction between the cell membrane and the electric and magnetic fields. Bacterial cell membranes are known to act as electrical capacitors as by carrying a layer of electric charge. When stimulated by electric and/or magnetic fields at the proper frequency, significant disruptions in the functions of the membranes as by disturbing the charge layers surrounding cells, are known to occur. When power levels are sufficiently high, cell membranes are known to rupture by a process called electroporation.